You are looking at the HTML representation of the XML format.
HTML is good for debugging, but is unsuitable for application use.
Specify the format parameter to change the output format.
To see the non HTML representation of the XML format, set format=xml.
See the complete documentation, or API help for more information. 
<?xml version="1.0"?>
<api>
  <query-continue>
    <allredirects garcontinue="Benito_Pablo_Juárez_and_Adoption|6381" />
  </query-continue>
  <query>
    <pages>
      <page pageid="5168" ns="0" title="Barbara Walters" />
      <page pageid="5365" ns="0" title="Baiteke (under Kiribati)" />
      <page pageid="5366" ns="0" title="Barbara La Marr" />
      <page pageid="5367" ns="0" title="Barbara Strozzi" />
      <page pageid="5368" ns="0" title="Barry Evans" />
      <page pageid="5369" ns="0" title="Basavis (under Devadasi)" />
      <page pageid="5370" ns="0" title="Bede, the Venerable" />
      <page pageid="5371" ns="0" title="Ben Andrews" />
      <page pageid="5372" ns="0" title="Ben Stein" />
      <page pageid="6424" ns="0" title="Bauro (under Kiribati)" />
    </pages>
  </query>
</api>